In a bid to crack down on the city's gun violence, the Chicago Police Department conducted a series of overnight raids in the South and West Side neighborhoods.

Of the 12 weapons seized, one was a "machine gun capable of firing 40 to 50 rounds in just a matter of seconds", Chief Anthony Riccio said.

President Donald Trump tweeted on Thursday about the seven homicides that occurred in Chicago on Wednesday, calling the situation there "totally out of control", and adding that Chicago "needs help".

Chicago Police arrested 81 people in overnight raids, the department's spokesman said Friday.

Riccio said the raids were executed only by Chicago Police, with no federal assistance. "If you're OK every day sitting by watching these people die and that's OK with you, then good luck on that". At the press conference, he said the police officers in the city needed "help from legislators and the criminal justice system".

Homicides are now outpacing last year in Chicago after the city experienced its deadliest day so far this year, according to data kept by the Tribune.

Johnson added, "We are nearly double in gun arrests than we were the same time a year ago - that's a ridiculous number". "That's a ridiculous number", Johnson said Friday. "We actually are doing something about it".

Chicago Police Superintendent Eddie Johnson says the raid won't eradicate all the violence, but is a "step in the right direction".